Hohfluh Lookout, Switzerland
— Viewed from atop this lookout in the Riederalp area northeast of Geneva, the Aletsch Glacier curves through a 2,000-meter- (1.2-mile) high valley like a massive freeway of packed ice – 23 kilometers (14.2 miles) long, 900 meters deep. The Aletsch is the largest glacier in the Alps. If melted, it would provide a liter of water a day for every inhabitant of Earth for six years.

When Europeans or scientists at the recent global Live Earth program want a quick data point for global warming, the Aletsch provides an example – even if not as dramatic a one as the melt flows in Greenland or Antarctica.

"I call it the retreat of the glacier," says Laudo Albrecht, a local director of Pronatura, an environmental group with 100,000 members in Switzerland.

The problem is not simply that the Aletsch is melting, scientists say. Glaciers have melted for 2,500 years in Europe; at one ice-age point, the Aletsch nearly covered local mountain peaks. What concerns scientists is the pace of the melt.

"Yes, it should retreat, but not so fast. The glacier is in rapid retreat, which is a fact and a clear sign of climate change," Mr. Albrecht says.

In the past 30 years, studies show, the Aletsch has been losing 50 meters of length a year and is thinning. Some years show gains in length, others record losses. But the overall figure is one of shrinkage. Last year, it lost 115 meters – though in 2004 and 2005, the glacier gained about 50 meters per year.

"At this rate, by 2100 about 80 percent of the surface of the glacier will be gone," says Ralph Logon, a Swiss geomorphologist and expert on glaciers.

Mr. Logon notes that while glacial melting is a long-term concern, it does not receive the same attention in Swiss cantonal politics as immediate problems of floods, avalanches, and other crises.

Yet the implication of glacier and ice cap melts are being seized, dramatically, by federal Europe. On the eve of a European Commission Green Paper released June 26 ("Adapting to Climate Change in Europe – Options for EU Action") EC President José Manuel Barroso visited the Greenland glacier of Sermeq Kujalleq in Ilulissat.

"Greenland is of major significance to the rest of the world in our struggle to halt climate change," Mr. Barroso told reporters afterward. "The ice is melting faster than anybody predicted…. 50 kilometers of ice [a year]… three times more than the Alps." Scientists argue that ocean levels could rise seven meters should Greenland's ice melt entirely.

The commission's report argues for dramatic prevention measures to combat the effects of a temperature rise. Within 40 years the effects of climate change could mean a need to "increase the height of dikes, [relocate] ports, industry, and entire cities and villages from low-lying coastal areas…."

Barroso says that the EC will push, at a UN climate summit in Bali this December, for a new treaty to replace the Kyoto Protocol, which ends in 2012.

Melting times

• Glaciers in the Alps have lost more than 20 percent of their area since the mid-19th century.

• While the thickness changes have fluctuated, losses of more than 1 meter of thickness have occurred in the past 15 to 20 years.

• Glaciers of less than100 meters are likely to disappear completely within the next 50 to 100 years, at this rate of change.